Homeostasis is the ability to maintain a relatively stable internal environment in an every-changing external environment. When the body is having trouble maintaining the balance, disease or even death may occur.
What an organism needs to maintain homeostasis-
  1. Nutrients
  2. Oxygen
  3. Water
  4. Body Temperature
  5. Atmospheric Pressure (Gases)

The primary systems that maintain this balance in the body are:
  • The Nervous System
  • The Endocrine System

Homeostatic Control Mechanisms-
  1. Stimulus-causes the imbalance within the internal environment (Ex: temperature)
  2. Receptors(sensors)- monitor the environment
  3. Receptors- Signals along the afferent pathways to the control center.

Two Negative Feedback Mechanisms:
  1. Negative Feedback Loop(most common): When the body is not in the optimal range it reacts to get back in the normal range
Ex) Starvation->Low Blood Glucose->Pancreas Converts Glycogen into Glucose->Normal Blood Glucose
2. Positive Feedback Loop: The initial stimuli causes an increasing reaction from the body.
Ex) Nursing a Baby->Oxytocin and Prolactin produced in the Pituitary Gland->Increase Milk Production